The direct to consumer model already exists. Amazon Kindle provides this very well on a per book level via Kindle [a la carte] (and also for large groups of books via Kindle Unlimited.) There are also numerous site-licensed services which give total access to books for a time period for pay -- I used it in grad school. I also subscribe to OReilly Safari and love it.
The OverDrive/Libby model exists because it is free to the end user -- the public library is verifying you are a local resident and then using local tax dollars to fund the free service to residents.